Aug 17, 2018 parosteal osteosarcomas are usually lowgrade tumors, however, sometimes they transform to highgrade tumors, which is named dedifferentiation. Note intact cortex otthe radius and thepoorly ossified periphery ofthe tumor, representing areas ofpredominant vol bc, no. However, fibrous or cartilaginous tissue may coexist or even predominate. Mri findings in parosteal osteosarcoma diagnostic and. Dedifferentiated parosteal osteosarcoma dpos is defined as a highgrade surface osteosarcoma which rarely occurs as either a primary or secondary event of conventional lowgrade parosteal osteosarcoma cpos. Departments of histopathology, enfield district hospital, enfield, middlesex and morbid anatomy, the london hospital, london, uk. Osteo boneosteoid tissue sarcoma malignant tumour of connective tissue 020412 dr.
Approximately 8% to 25% of the cases reported in literature developed dedifferentiation, which was reported to had increase. Parosteal osteosarcoma of the orbit is a rare entity, with only 3 presumed cases having been reported in the literature to date. Fewer than 50 cases of osteosarcoma involving the hand have been reported in the literature. Parosteal osteosarcoma is a subtype of osteosarcoma and arises from the outer layer of the periosteum. Gnas mutations are not detected in parosteal and lowgrade. Parostealt osteosarcoma is situated on the bone surface usually distally on the femur and show a low grade fibroblastic growth pattern with bone production. It accounts for about 4% of all osteosarcomas and, although rare, it is the most common type of osteosarcoma of the bone surface. Other cell populations may also be present, as these types of cells may. It typically presents in early adulthood and middle age with a.
Parosteal osteosarcoma atlas of musculoskeletal oncology. Its relatively benign course was described by muller as early as 1843, but it was not before 1947 that parosteal. Osteosarcoma is the most common malignant bone tumor. We report a case of parosteal osteosarcoma arising in the metacarpal. Gnathic osteosarcoma jaw bones usually chondroblastic. These cells produce osteoid describing irregular trabeculae amorphous, eosinophilicpink with. It typically presents in early adulthood and middle age with a peak incidence in the third decade. Parosteal osteosarcoma of the proximal phalanx of a finger. Giant cell rich parosteal osteosarcoma, histopathology. Parosteal osteosarcoma is a lowgrade malignant tumor which is capable of dedifferentiation. Parosteal osteosarcoma occurs in the periosseous tissues. Parosteal osteosarcoma radiology reference article.
Only 12 cases of intraoral parosteal osteosarcomas have been reported in. Parosteal osteosarcoma, secondary chondrosarcoma are also confusing at times in histopathology findings. You may not embed one of our images on your web page without a link back to our site. We report two cases mimicking an osteochondroma, radiologically and histologically and propose an explanation. Histopathology and molecular pathology of bone and extraskeletal osteosarcomas helen trihia and christos valavanis metaxa cancer hospital, department of pathology and molecular pathology unit greece 1.
Recently, we encountered a patient with dedifferentiated parosteal osteosarcoma occurring in the maxilla. Departments of ophthalmology and histopathology, aristotle university of thessaloniki, thessaloniki, greece. Several incidences of dedifferentiation in cpos were reported by earlier studies 1824% 1,2,3. A system commonly used to stage osteosarcoma is the msts system, also known as the enneking system. The findings are correlated with histopathologic results. Osteosarcoma is thought to arise from primitive mesenchymal boneforming cells, and its histologic hallmark is the production of malignant osteoid. Here, we report a first case of dedifferentiated parosteal osteosarcoma of the head and neck. We describe an extraordinary case of such a tumour arising from the skull vault. Jun 28, 2014 parosteal osteosarcomas are rare, lowgrade juxtacortical variant of osteosarcoma, especially in the jaws, representing 1. Pdf to assess the role of magnetic resonance imaging mri, particularly signal. In single cases the underlying cortex and bone marrow might be infiltrated.
Ahuja and coauthors and, more recently, ritschl and coauthors have tended to consider all surface osteosarcomas to be parosteal and have distinguished them by the histologic grade. Webpathology is a free educational resource with 10328 high quality pathology images of benign and malignant neoplasms and related entities. If you would like a large, unwatermarked image for your web page or. Heavily ossified, hard, tanwhite, somewhat lobulated mass attached to the underlying cortical bone. It arises from the surface of the bone, namely the outer layer of the periosteum.
Parosteal osteosarcoma is a welldifferentiated variant of osteosarcoma that affects the surface of the bone. The most commonly affected sites, in descending order, are the distal femur typically the posterior surface, the proximal humerus, the proximal femur, the proximal tibia, and the proximal ulna. Parosteal osteogenic sarcoma of the hand walt 1990 histopathology wiley online library skip to article content. Mar 16, 2020 webpathology is a free educational resource with 10328 high quality pathology images of benign and malignant neoplasms and related entities. Most of the neoplastic bone lacked osteoblastic rimming. Parosteal osteosarcoma is a lowgrade, malignant bone tumor that usually arises on the metaphyseal surface of long bones. It has not been described to arise from sites other than the major tubular bones. They are rare, slowly growing tumours whose clinical behaviour and radiological and pathological appearances are vastly different from those of conventional osteosarcoma. Tumor cells are very pleomorphic anaplastic, some are giant and present numerous and atypical mitotic figures.
Osteosarcoma osteogenic sarcoma is a malignant tumor whose neoplastic cells present osteoblastic differentiation and form tumor bone. Of the 147 conventional parosteal osteosarcoma, 119 87. Dedifferentiated parosteal osteosarcoma of the maxilla. Histopathology and molecular pathology of bone and. The vast majority involve the metaphysis of the femur, humerus, or tibia. Parosteal osteogenic sarcoma of the hand walt 1990. Parosteal osteosarcomas are rare, lowgrade juxtacortical variant of osteosarcoma, especially in the jaws, representing 1. Introduction osteosarcoma has been recognized for almost two centuries and is the most common. Possibilities, in this case, are nonhereditary solitary exostosis,5,6 bpop,14,7,8 turret exostosis, and florid reactive periosteitis. There was no spatial relationship between the giant cells and areas of. Most common type of juxtacorticalsurface osteosarcoma. References 1 article features images from this case. Parosteal osteoid sarcoma, sometimes referred to asjuxtacortical osteogenic sarcoma, is a rare malignant bone tumor which must be differentiated from an osteosarcoma clinically, roentgenologically, and histologically. It has a slight female predominance and most frequently occurs in the third decade of life, 2 which is a decade older than the peak age of the conventional counterpart.
Parosteal os is composed by spindle cells and collagen fibers embedding osseous trabeculae. Presentations ppt, key, pdf logging in or signing up. Bizarre parosteal osteochondromatous proliferation arises. Unlike conventional osteosarcomas, it involves an older age group typically in the 3 rd and 4 th decades of life and shows a slight female predilection 1, 3, 4. The most common type of osteosarcoma is the primary, high grade, intramedullary conventional osteosarcoma, which represents approximately 75% of all osteosarcomas definitions. Unlike conventional osteosarcomas, it involves an older age group typically in the 3 rd and 4 th decades of life and shows a slight female. Giant cell rich parosteal osteosarcoma, histopathology 10. The classic or socalled conventional osteosarcoma develops in the medullary cavity of the metaphysis of long bones. Osteosarcoma os is a malignant spindle cell sarcoma in which the malignant cells produce osteoid or bone in the background of a sarcomatous stroma. It is a highgrade sarcoma, very aggressive, without escape in terms of surviving. Diagnostic evaluation and biopsy techniques for primary bone tumors, an overview of treatment and outcomes, principles guiding surgical management of bone sarcomas, and chemotherapy in the. Nov 14, 2019 parosteal osteosarcoma occurs in the periosseous tissues. Surface tumours of bone may be a cause of confusion and diagnostic difficulty.
The grade g of the tumor, which is a measure of how likely it is to grow and spread, based on how it looks under the microscope. Reviewing the records, bone scans with technetium 99m, radiographs, arteriography, ct, mri and histopathology findings showed 6 patients with the confirmed diagnosis of parosteal osteosarcoma and one was with a. Diagnostic difficulties may arise from the lack of awareness of less common entities, insufficient biopsy sampling and a failure to understand the precise relationship of a lesion and the bone surface. About 50% of these tumors demonstrate chondroid differentiation. Features are consistent of parosteal osteosarcoma which is low grade tumor arising from the outer periosteal layer. Confusion may arise from the several descriptive adjectives used parosteal, periosteal and juxtacortical. Diagnostic and treatment problems with parosteal osteosarcoma. Intracortical osteosarcoma is very rare highgrade osteosarcoma that from histological point of view is osteoid or maybe bone formation.
It most commonly occurs in young women over the metaphyseal. Conventional osteosarcoma with periosteal spread high grade surface osteosarcomas. Cells form long sweeping fascicles with parallel nuclei. Periosteal osteosarcoma, as described in chapter 11, is distinctly different from parosteal osteosarcoma radiographically and histologically. Medullary extension of parosteal osteosarcoma has been seen in 22% to 58% of patients, and this finding itself is not considered significant in the prognosis. Parosteal osteosarcoma pos is a slowgrowing tumor which originates from the outer layer of the periosteum and represents 65% of surface osteosarcomas and in our database accounts approximately for 4, 8% of all osteosarcomas. Trabeculae appear also as parallel streamers with broken cement lines as pagetic mosaic.
Only 12 cases of intraoral parosteal osteosarcomas have been reported in the english literature. It is treated like conventional osteosarcoma figures 5,6. Multifocal osteosarcoma is unusual, affect children, young adults. Parosteal osteosarcoma of the skull, histopathology 10. It is the most common type of juxtacortical or surface osteosarcoma and accounts for 5% of all osteosarcomas. Parosteal osteosarcoma definition of parosteal osteosarcoma. Compared with conventional osteosarcoma, parosteal osteosarcoma differs in prevalence with regard to sex and age. Dec 17, 2018 parosteal osteosarcoma shows cartilaginous cap that can be confused with osteosarcoma ct or mri scan of the affected region microscopic and pathological evaluation of tissue biopsy the specimen is examined under a microscope by a pathologist, to arrive at a definitive diagnosis. Dedifferentiated parosteal osteosarcomas, which are high grade lesions, can occur in a wide age distribution. Convention foc fibroblastic, osteogenic, chondroblastic. Parosteal osteosarcoma is a lowgrade, malignant, boneforming tumor that arises on the surface of bone. Histopathology and molecular pathology of bone and extraskeletal osteosarcomas. On histology the tumour was dominated by large numbers of osteoclast. Parosteal osteosarcoma is a low grade, well differentiated fibroblastic tumor that produces boneosteoid immature woven bone.
Parosteal osteosarcoma shows cartilaginous cap that can be confused with osteosarcoma ct or mri scan of the affected region microscopic and pathological evaluation of tissue biopsy the specimen is examined under a microscope by a pathologist, to arrive at a definitive diagnosis. They are directed toward diaphysis and may have medullary canal is in continuity with that of the. I parosteal osteosarcoma i43 cartilaginous and fibrous tissue. A parosteal osteosarcoma of the distal femur with a typical radiographic and macroscopic appearance is reported. By histopathological examination there were 6 grade. The tumor is usually located at the posterior aspect of the distal femur in about 70% of cases, followed by the. M alignant bone tumors are rarely seen in the hand. Parosteal osteosarcoma is a rare malignant bone tumor arising from the bone cortical surface.
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